db.describe and mysql

[fpouw]

A query result form this component causes v.db.addcolumn and (consequently) v.db.join to fail.

db.describe reports the mysql "double" tables as

column:cat description: type:DOUBLE PRECISION len:22 scale:0 precision:31 default: nullok:yes select:? update:?

When the len value (e.g. 22) is then used by the v.db.join function (which calls v.db.addcolumn), the process fails in the execution of the mysql command:

ALTER TABLE <table_name> ADD COLUMN <column_name> DOUBLE PRECISION(22)

This is because mysql expect the format: ...DOUBLE PRECISION(M,D).

"Here, “(M,D)” means than values can be stored with up to M digits in total, of which D digits may be after the decimal point." from: ​http://dev.mysql.com/doc/refman/5.7/en/floating-point-types.html

[martinl]

Attempt to fix this issue in r67376.

[martinl]

Backported in r67411. Closing the ticket feel free to re-open if needed.